Return the sum of the current size of this deque plus the minimum number of push_front or push_back operations needed to invalidate iterators in this deque. Note that this method is not part of the C++ standard.
push_front
push_back
Declared in <bslstl_deque.h>
<bslstl_deque.h>
Deque_Base<VALUE_TYPE>::size_type capacity() const noexcept;